We've all seen it. A guy struggles mightily to complete a single rep on a heavy deadlift. His eyes are almost bursting out of their sockets. You think he's going to pass out... and then he proceeds to do 6 MORE reps with that weight!
We call that a "bounce-and-go" deadlift. Here's what it looks like, though we didn't want to actually hurt our exercise model, so he's using a light weight:
Now, getting six more reps with a weight you were barely able to lift on the first rep is pretty much impossible to do without some "help" – letting the bumper plates bounce on the floor to rebound back up. Think that's no big deal? A good bounce can give you up to 6 inches of assistance, which is substantial.
"Bounce and go" is the evil brother of the "touch-and-go," which is an acceptable technique. Sadly, when people say they're doing touch-and-go deadlifts, most of them let the bar bounce because they can either use more weight or crank out reps faster.
The whiplash effect
In order to catch a big rebound, the lifter will need the barbell to speed up on its way down. To do that he instinctively loses tightness and may even use spinal flexion instead of the hip hinge to slam the bar down.
The lower back, glutes, and hams become relaxed to let the bar fall as fast as possible. Then the bar hits the ground and bounces up. It will go up a few inches mostly using its own momentum, after which it wants to go down and that's where the muscles take over.
The prime movers are relaxed and they must suddenly contract all-out to absorb the weight and pull it up. This is a tremendous shock for the body, and it's even worse because you'll be in a bad posture most of the time. Since the glutes are harder to recruit, the lower back and hams will take the brunt of the stress. Hello, lower back injury or hamstring pull!
Detraining the bottom portion of the lift
If the momentum from the rebound is what makes the barbell break off of the floor and move up those first few inches, the nervous system learns not to produce maximum tension in that portion of the range of motion. In fact, it learns to become relaxed in that position.
As a result, you'll develop a significant sticking point breaking the barbell off the floor or during the first pull. So your reps might go up, but your maximal strength on the lift won't because that first pull will always stay weak.
You learn to deadlift from the floor using a different posture. Think about it. If you do 8 reps and use the bounce while relaxing your trunk muscles to produce a bigger rebound, you'll practice good position and technique on ONE rep (if that) and bad positions on all the other proceeding reps. Which do you think will have the greatest motor learning impact?
What will happen is that with submaximal weights you'll be able to force yourself to maintain a proper position from the floor, but as soon as the weight gets heavy you'll go to your default mode, which is whatever you practice the most.
The bounce-and-go doesn't have a place in the training for 90% of the population. The only exceptions are:
- During a CrossFit competition: Competition is the key word here because in training (yes, that means every WOD not done in a competition) you should avoid the bounce. Use the touch-and-go method. You'll go slower but the training effect will be much greater and you'll experience more potential for hypertrophy too.
- As an overload exercise to strengthen the second portion of the deadlift: The bounce allows you to do higher reps with a heavier weight. The first portion isn't trained that much but the second half of the pull is being overloaded.
This is a very advanced technique that should only be used by experienced lifters who have perfect technique already, and they should only do it for 1-2 weeks. Don't do it if you can't maintain perfect position and tension during the bounce. If you lose one of the two to catch a bigger rebound, skip the method altogether.